Obfuscated npm Preinstall Payload Execution via ChainDrop Math Symbol Script (via process_creation)

ATT&CK techniques

Initial Access → Execution

Recon
Resource Dev
Initial Access
- T1195.002Compromise Software Supply Chain
Execution
- T1059.007JavaScript
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule detects execution of the ChainDrop npm worm payload scripts, in which a hidden preinstall setup.mjs downloads a Bun runtime and runs the obfuscated Math_Symbol.js during package installation. Adversaries abuse npm lifecycle hooks to trigger credential-stealing code automatically on install and self-propagate through stolen publishing tokens, making early detection critical for stopping supply-chain compromise before secrets are exfiltrated.

Reporting behind it

Related detections9 linkedT1059.007 — drag to rearrange

Malicious npm Package Browser Wallet-Hijack Interceptor via Script Content

Suspicious Obfuscation Marker in JavaScript Bundle from Compromised npm Package

Malicious Mini Shai-Hulud npm Dropper node setup.mjs from IDE Hook Dirs (via process_creation)

Malicious Shai-Hulud npm Worm Marker via SHA1HULUD Process Name (via process_creation)

Malicious Node.js Execution of Hidden .claude Setup Script

Suspicious npm Postinstall Node Execution From Fixtures Path (BeaverTail OtterCookie)

Suspicious NPM Install Hook Executing Setup Script via Node

Malicious Bun Runtime Payload Dropped by Shai Hulud npm Supply Chain Attack

Malicious Shai-Hulud Bun Payload Execution via npm Preinstall Script (via process_creation)

Obfuscated npm Preinstall Payload Execution via ChainDrop Math Symbol Script (via process_creation)

Pivot detection · T1059.007 · 9 related

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

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